[klibc] fwd: fix up ARM assembly to use 'bx lr' in place of 'mov pc, lr'.

[Kirill A. Shutemov]

On Thu, Feb 17, 2011 at 12:06:48AM +0100, maximilian attems wrote:
> hello vorlon,
> 
> got notified of your patch,
> will apply next days upstream unless some critiques are voiced on ml.
> thanks.
> 
> -- 
> maks
> 
> 
> ----- Forwarded message from Steve Langasek <steve.langasek at canonical.com> -----
> 
> Date: Wed, 16 Feb 2011 22:05:42 -0000
> From: Steve Langasek <steve.langasek at canonical.com>
> Subject: [Bug 527720] Re: thumb2 porting issues identified: klibc uses mov.*pc
> 
> 
> I've also touched it up to be mergeable with Debian (support v4t builds
> with #ifdef).
> 
> Confirmed that installing the resulting klibc packages on my beagleboard
> gives me a successfully-booting initramfs with klibc; and the
> vfork/setjmptest test cases all pass in the klibc package tree.
> 
> Fixes: https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/527720
> 
> --- klibc-1.5.20.orig/usr/klibc/arch/arm/vfork.S
> +++ klibc-1.5.20/usr/klibc/arch/arm/vfork.S
> @@ -25,7 +25,11 @@ vfork:
>          ldrcs	r3, 1f
>          mvncs	r0, #0
>          strcs	r2, [r3]
> +#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)

NAK. ARMv4T supports bx intruction. ARMv4 doesn't.

>  	mov	pc, lr
> +#else
> +	bx	lr
> +#endif
>  
>  	.balign 4
>  1:
> @@ -49,7 +53,11 @@ vfork:
>  	str	r2, [r1]
>  	neg	r0, r0
>  1:
> +#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
>  	mov	pc, lr
> +#else
> +	bx	lr
> +#endif
>  
>  	.balign	4
>  2:
> --- klibc-1.5.20.orig/usr/klibc/arch/arm/setjmp.S
> +++ klibc-1.5.20/usr/klibc/arch/arm/setjmp.S
> @@ -29,7 +29,11 @@
>  setjmp:
>  	stmia	r0, {r4, r5, r6, r7, r8, r9, r10, fp, sp, lr}
>  	mov	r0, #0
> +#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
>  	mov	pc, lr
> +#else
> +	bx	lr
> +#endif
>  	.size setjmp,.-setjmp
>  
>  	.text
> @@ -39,7 +43,11 @@ setjmp:
>  longjmp:
>  	ldmia	r0, {r4, r5, r6, r7, r8, r9, r10, fp, sp, lr}
>  	mov	r0, r1
> +#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
>  	mov	pc, lr
> +#else
> +	bx	lr
> +#endif
>  	.size longjmp,.-longjmp
>  
>  #else /* __thumb__ */
> @@ -75,7 +83,11 @@ setjmp:
>  	mov	r7, sp
>  	stmia	r0!, {r3, r4, r5, r6, r7}
>  	mov	r0, #0
> +#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
>  	mov	pc, lr
> +#else
> +	bx	lr
> +#endif
>  	.size setjmp,.-setjmp
>  
>  	.text
> @@ -96,7 +108,11 @@ longjmp:
>  	mov	r0, r1
>  	bne	1f
>  	mov	r0, #1
> +#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
>  1:	mov	pc, r3
> +#else
> +1:	bx	r3
> +#endif
>  	.size longjmp,.-longjmp
>  
>  #endif /* __thumb__ */
> 
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-- 
 Kirill A. Shutemov